[VulnWatch] iDEFENSE Security Advisory 06.23.05: Veritas Backup Exec Agent Error Status Remote DoS Vulnerability

From: iDEFENSE Labs (labs-no-reply_at_idefense.com)
Date: 06/23/05

  • Next message: iDEFENSE Labs: "[VulnWatch] Veritas Backup Exec Remote Agent NDMLSRVR.DLL DoS Vulnerability: Veritas Backup Exec Remote Agent NDMLSRVR.DLL DoS Vulnerability"
    Date: Thu, 23 Jun 2005 17:44:05 -0400
    To: <bugtraq@securityfocus.com>, <vulnwatch@vulnwatch.org>, <full-disclosure@lists.grok.org.uk>
    
    

    Veritas Backup Exec Agent Error Status Remote DoS Vulnerability

    iDEFENSE Security Advisory 06.23.05
    www.idefense.com/application/poi/display?id=271&type=vulnerabilities
    June 23, 2005

    I. BACKGROUND

    VERITAS Backup Exec is an advanced backup and restore solution for
    Microsoft Windows server environments. More information is available
    from the vendor's website:

    http://veritas.com/Products/www?c=product&refId=57

    II. DESCRIPTION

    Exploitation of a buffer overflow vulnerability in Veritas Software
    Corp.'s Backup Exec allows remote attackers to execute arbitrary code.

    The Veritas Backup Exec Agent listens on TCP port 10000 and is
    responsible for accepting connections from the backup server when a
    backup is to occur. Typically the agent would be installed on most
    servers and important workstations in an enterprise environment.
    Veritas Backup Exec uses the standard NMDP protocol to communicate with
    the listening agents.

    The vulnerability specifically exists because of improper handling of
    request packets with an unexpected "Error Status" value. Specifically,
    any Error Status other than "0" will cause a null pointer dereference,
    resulting in an unhandled exception as can be seen as follows.

    eax=00000000 ebx=0032ac08 ecx=00000000
    edx=0098a930 esi=0032e1e8 edi=009b5770
    eip=008f1c84 esp=00fbfb58 ebp=0032ac30 iopl=0
    nv up ei pl nz na pe nc
    cs=001b ss=0023 ds=0023 es=0023 fs=003b gs=0000 efl=00010202

    *** ERROR: Symbol file could not be found.
    Defaulted to export symbols for
    C:\Program Files\VERITAS\Backup Exec\NT\ndmpsrvr.dll -
    ndmpsrvr+0x21c84:

    008f1c84 8b00 mov eax,[eax] ds:0023:00000000=????????

    The unhandled exception will result in a crash of the program and a
    denial of service condition.

    III. ANALYSIS

    Exploitation does not require authentication, thereby allowing any
    remote attacker to cause the denial of service and disruption of backup
    capabilities.

    IV. DETECTION

    iDEFENSE has confirmed the existence of this vulnerability in Backup
    Exec for Windows Servers versions 9.0, 9.1 and 10.0. It is suspected
    that other versions are also vulnerable.

    Several vendors ship or use Veritas software including Hitachi and NEC
    Corporation.

    V. WORKAROUND

    Use a firewall to restrict incoming connections to trusted workstations
    running the Backup Exec client software which uses port 10000 TCP.

    VI. VENDOR RESPONSE

    The vendor has addressed this vulnerability in security advisories
    VX05-001 and VX05-008:

       http://seer.support.veritas.com/docs/276533.htm
       http://seer.support.veritas.com/docs/277485.htm

    VII. CVE INFORMATION

    The Common Vulnerabilities and Exposures (CVE) project has assigned the
    name CAN-2005-0772 to this issue. This is a candidate for inclusion
    in the CVE list (http://cve.mitre.org), which standardizes names for
    security problems.

    VIII. DISCLOSURE TIMELINE

    03/16/2005 Initial vendor notification
    03/30/2005 Initial vendor response
    06/22/2005 Coordinated public disclosure

    IX. CREDIT

    The discoverer of this vulnerability wishes to remain anonymous.

    Get paid for vulnerability research
    http://www.idefense.com/poi/teams/vcp.jsp

    Free tools, research and upcoming events
    http://labs.idefense.com

    X. LEGAL NOTICES

    Copyright (c) 2005 iDEFENSE, Inc.

    Permission is granted for the redistribution of this alert
    electronically. It may not be edited in any way without the express
    written consent of iDEFENSE. If you wish to reprint the whole or any
    part of this alert in any other medium other than electronically, please
    email customerservice@idefense.com for permission.

    Disclaimer: The information in the advisory is believed to be accurate
    at the time of publishing based on currently available information. Use
    of the information constitutes acceptance for use in an AS IS condition.
    There are no warranties with regard to this information. Neither the
    author nor the publisher accepts any liability for any direct, indirect,
    or consequential loss or damage arising from use of, or reliance on,
    this information.


  • Next message: iDEFENSE Labs: "[VulnWatch] Veritas Backup Exec Remote Agent NDMLSRVR.DLL DoS Vulnerability: Veritas Backup Exec Remote Agent NDMLSRVR.DLL DoS Vulnerability"

    Relevant Pages